RED-CELL POTASSIUM IN CHRONIC FETAL ASPHYXIA

Summary

A study of the relationship between acid-base balance and red-cell potassium has been undertaken on maternal and fetal blood in 141 subjects. Metabolic acidosis resulting from chronic fetal asphyxia as determined by low blood pH, high Pco₂, low standard bicarbonate and high lactic acid values is associated with a fall in red- cell potassium and a rise in plasma potassium in cord arterial blood. In cord venous blood, a significant positive relationship between red-cell potassium and pH was demonstrated, but a relationship between plasma potassium and red-cell potassium could not be demonstrated. These findings suggest that correction of plasma potassium occurs in the passage of fetal blood through the placenta and that a depletion of red-cell potassium occurs under conditions of fetal acidosis until a new equilibrium is reached.